The present invention relates generally to operations performed and equipment utilized in conjunction with a subterranean wellbore and, in an embodiment described herein, more particularly provides a method of tracking fluid displacement along a wellbore using real time temperature measurements.
In well production and injection operations, it is known to use a distributed temperature survey (DTS) to sense temperature along a wellbore. For example, in stimulation operations a temperature profile may be generated after the operation is completed, and the temperature profile may be used to determine where the injected fluid entered formations or zones intersected by a wellbore. This information is useful in evaluating the effectiveness of the stimulation operation, and in planning future stimulation operations in the same, or a different, wellbore.
Unfortunately, these methods do not provide an operator with the information needed in real time, while the operation is progressing, to evaluate how the operation could be modified to improve the results of the operation. In addition, these methods rely on detecting temperature variations which are limited by various factors, including the difference between surface and downhole temperatures, properties of the fluids flowed in the wellbore, etc.
Therefore, it may be seen that improvements are needed in the art of tracking fluid displacement in a wellbore. It is among the objects of the present invention to provide such improvements, which may be useful in various operations, including but not limited to production, injection, stimulation, completion, testing, fracturing, conformance, etc.